content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package hu.akarnokd.reactive4javaflow.impl.consumers;
  
  import hu.akarnokd.reactive4javaflow.FolyamSubscriber;
  import hu.akarnokd.reactive4javaflow.impl.*;
  
  import java.lang.invoke.*;
  import java.util.concurrent.Flow;
  
  public final class StrictSubscriber<T> implements FolyamSubscriber<T>, Flow.Subscription {
  
      final Flow.Subscriber<? super T> actual;
  
      Flow.Subscription upstream;
      static final VarHandle UPSTREAM = VH.find(MethodHandles.lookup(), StrictSubscriber.class, "upstream", Flow.Subscription.class);
  
      long requested;
      static final VarHandle REQUESTED = VH.find(MethodHandles.lookup(), StrictSubscriber.class, "requested", Long.TYPE);
  
      Throwable error;
      static final VarHandle ERROR = VH.find(MethodHandles.lookup(), StrictSubscriber.class, "error", Throwable.class);
  
      int wip;
      static final VarHandle WIP = VH.find(MethodHandles.lookup(), StrictSubscriber.class, "wip", Integer.TYPE);
  
      public StrictSubscriber(Flow.Subscriber<? super T> actual) {
          this.actual = actual;
      }
  
      @Override
      public void onSubscribe(Flow.Subscription subscription) {
          actual.onSubscribe(this);
          SubscriptionHelper.deferredReplace(this, UPSTREAM, REQUESTED, subscription);
      }
  
      @Override
      public void onNext(T item) {
          HalfSerializer.onNext(actual, this, WIP, ERROR, item);
      }
  
      @Override
      public void onError(Throwable throwable) {
          HalfSerializer.onError(actual, this, WIP, ERROR, throwable);
      }
  
      @Override
      public void onComplete() {
          HalfSerializer.onComplete(actual, this, WIP, ERROR);
      }
  
      @Override
      public void request(long n) {
          if (n <= 0L) {
              cancel();
              onError(new IllegalArgumentException("§3.9 violated: positive request amount required"));
          } else {
              SubscriptionHelper.deferredRequest(this, UPSTREAM, REQUESTED, n);
          }
      }
  
      @Override
      public void cancel() {
          SubscriptionHelper.cancel(this, UPSTREAM);
      }
  }
  